1. Field of the Invention
The present invention relates to an imaging apparatus such as digital camera, and more particularly to an imaging apparatus having a memory management unit for managing a virtual memory.
2. Related Art
A digital camera has recently made drastic technical progress, and is going to surpass the conventional film type camera on market. Concerning continuous shooting, film type camera has a problem with taking time in winding up the film. Continuous shooting with digital camera provides a problem that further image cannot be taken while image data is being written into recording medium. Several technologies have been proposed as measures for solving such problem in digital camera.
For example, patent document 1 discloses an imaging apparatus in which the maximum number of images that can be recorded in temporary storage device has been set, the number of stored images is counted, and if the counted number of images is less than the maximum number of images that can be recorded in temporary storage device, then imaging is permitted. In this method, however, since the maximum number of images is determined in advance to the imaging mode, the user may often miss the shooting chance when desired to image sequentially, and the temporary storage device may not be always utilized to the maximum extent.
Patent document 2 discloses a configuration for controlling the number of images of continuous shooting depending on the duration of pressing of imaging button, in addition to the configuration of patent document 1. In this case, however, the number of images of continuous shooting is limited by the maximum number of recordable images, the number of images of continuous shooting depends on the delicate control by the finger tip, and the configuration is hard to use. The image data is compressed and converted, and the processing time of compression and conversion is longer than the taking time of one image. In this configuration, therefore, two memories for storing data are provided before and after the compressing and converting circuit, thus to allow continuous shooting until one memory is fully filled up. However, if the memory is filled up, continuous shooting is stopped if continued to press the shutter release button.
Patent document 1: JP 2002-152573A
Patent document 2: JP 2001-57647A
These prior arts are commonly controlled to manage the memory capacity by the number of images, not by the memory capacity, and hence the number of images in continuous shooting is limited, and flexibility of operation of the imaging apparatus is not sufficient.